This invention relates to explosive perforation devices. More particularly the invention relates to an explosive perforation device that utilizes the shaped charge principle in order to perforate a target and inject a material through the perforation for disrupting structures behind the target. The present invention is particularly adapted to disarm other explosive devices such as bombs without detonation of the bomb.
Heretofore, when it has been required to dispose of hazardous devices such as unexploded bombs it has been necessary to either actually detonate the bomb or to render it inactive by use of various techniques; one of which is by drilling a hole therein and inserting a material, such as water, into the interior of the interior of the explosive device. When actually detonating the explosive device, generally it must be relocated to an area that can sustain the explosion without endangering the surrounding area or personnel. When disarming an explosive device by physically making an opening and then inserting a disruptive material therein the danger of explosion is great due to metallic fragments and sparks created by the entry mechanism. Often times the explosive device to be deactivated may be located in a place from which it can not be removed or, such that movement would present a formidable task and danger. In such cases the bomb obviously can not be exploded and present methods of deactivation can be extremely hazardous. It is therefore highly desirable to have means of remotely penetrating the bomb and injecting a disruptive material for deactivation of any detonator means therein while reducing the threat of possible detonation from that when present devices are used.
Perforation devices have been devised that utilize shape charge principles and means for inserting a liquid through the perforation for disrupting structure behind the target. Such a device is disclosed in A. Venghiattis U.S. Pat. No. 3,190,329 for Perforating Device. However, contrary to the present invention, this device does not use shaped charge principles. While this device is suitable for penetration and insertion of a disruptive material, it is not suited for use in disarming hazardous devices because it does not eliminate the threat of detonation. Devices as disclosed by Vanghiattis will fragment and send metallic particles from the liner and case into the target along with the disruptive material. As previously stated, these metallic fragments can cause an explosive device to detonate. Additionally, because the walls or the case of such devices fragment due to the internal pressures created, the liquid material is not driven forward in a well defined path. Rather, the stream of liquid tends to expand radially away from the trajectory required to insert the material into the perforation. Consequently, a substantial portion of the disruptive material will merely splatter around the perforation.
The shortcomings of the A. Venghiattis' Perforating Device are not a significant problem when the device is used for its intended purpose of perforating well casings and disrupting the structure therebehind. In such application the device is placed in intimate contact with the target which assures eventual insertion of the material. Fragmentation is also a desired effect for loosening densely packed material behind the target.
On the other hand, when perforating thick steel casings of bombs, the explosive powered device is normally located at a distance from the target so as to generate efficient jet for penetration and perforation without transmitting the direct shock of the explosion, thereby requiring means for assuring that the disruptive material is propelled in as straight and well defined a trajectory and configuration as possible.
To prevent fragmentation and to direct the disruptive material has heretofore required extremely thick case walls. This is undesirable because the size, weight, cost, and managability of such devices becomes unreasonable.